There’s no one-size-fits-all formula when it comes to choosing the kind of polyester on which you’d like to print. Various blends, from polyester/cotton to polyester/viscose, have different challenges when screen printing.
Polyester, first introduced to the American public in 1952, is famous for its wrinkle resistance, durability, hypoallergenic qualities and its ability to wick moisture. Fortunately, polyester does not need to be pre-shrunk like cotton. Though a synthetic fiber, polyester is naturally resistant to staining and resists shrinking, providing a magical combination of convenience.
We’ve listed five key tips for screen printing on polyester to help you begin your project:
Pick the Right Polyester for your Screen Printing Project
Different kinds of polyester blends have their own challenges. Depending on its fiber ratio, polyester mixed with other fibers might prevent the ink from properly absorbing. For example, during the curing process, a 50/50 blend of polyester and cotton may cause dye migration, or color bleeding, potentially changing the color.
To avoid dye migration, make sure you pick the right polyester blend for your project and, during the curing process, avoid heating the fabric too much. A 100% polyester blend will allow ink to cure well, while anything less than 65% polyester may cause curing issues.
Need a little more help on choosing the right t-shirt? Read up on some of our tips on choosing the perfect tee to screenprint on in our blog post, here!
Choose the Right Dye for the Project
Working with polyester requires experimenting with ink before you bring your project to mass production. The type of ink you’ll choose depends on your goals.
Several kinds of inks exist. Plastisol ink is synthetic and bright, while water-based ink is more eco-friendly and softer to the touch. This is because water-based ink absorbs into fabric, while plastisol sits on top of it creating a stiff feel. For polyester, start with a thin layer of low-bleed or no bleed inks in order to prevent dye migration.
Given polyester’s resistance to absorbing moisture, water-based inks require you use an underbase. Unlike plastisol ink, water-based inks dry out faster, limiting its workability. So if you want to use water-based ink, add a discharge agent (or underbase), but you’ll only have 48 hours to work the fabric.
Use an Underbase for Light or Dark Fabrics
You may need to use an underbase depending on the color of the polyester you’ve chosen. This is because various inks act differently on light or dark fabric.
To help prevent dye migration, use one-stoke white or gray underbase. One-stroke white is formulated to help block dye migration. Once the underbase is laid, any color of plastisol may be applied to it. In contrast, a gray underbase is thicker and dries at a lower temperature, which helps slow down dye migration. Since it’s thicker, gray underbase works best on sports apparel rather than for projects meant to drape elegantly.
Address Ink Drying Concerns During the Flash Cure
Prior to the final cure, dyes can migrate if you heat up your fabric too much under your flash cure. Flash your image onto the substrate only as long as the image needs to cure. Temperature tape may help you gauge the temperature of your fabric under the flash cure or on the conveyor dryer.
If you’re still having trouble getting the ink to cure above 300 degrees Fahrenheit, a permaset synthetic fixer can help to set ink that would otherwise be difficult to adhere to polyester.
Regardless of what inks you use to screen print on polyester, you’ll need to test your inks on your chosen fabrics to avoid color bleeding.
Use a Slip Sheet to Keep Artwork Flat During the Heat Process
Because it’s a synthetic fiber, polyester requires using a slip sheet during the application and curing process. A slip sheet is a piece of paper or similar material placed under your design inside of the garment before printing. Polyester’s weave has many air gaps between threads, allowing ink to pass through. This most commonly occurs when printing white ink on dark polyester fabrics.
Learning a new technique is always challenging, so make sure to do several test runs. If you want to screen print on polyester, consider these guidelines from Clothing Shop Online for a frustration-free process and crisp designs!
Looking for more screen printing tips? Check out our blog that gives you 5 tips for screen printing on cotton!